Clamping bodies of this type formed as a screw connection are, for example, used in electric terminals, such as terminal blocks or lustre terminals. Electric terminals with a screw connection are distinguished by their high clamping forces that can be transmitted constantly to electric conductors over many years. With this type of terminal, predetermined high clamping forces can be maintained without fluctuations even when vibrations act on the electric terminal. Because of these properties, electric terminals with a screw connection are also preferably used in demanding industrial applications with moving and vibrating machine parts.
The clamping body is generally arranged in an insulating material housing to form an electric terminal. The clamping body pocket of the clamping body may be formed from an electrically conductive material. A threaded bore, which is guided into the receiving space of the clamping body and in which a screw is inserted, is formed on a lateral wall of the clamping body pocket. The screw head of the screw is accessible via an opening provided in the insulating material housing, so the screw can be screwed with its tip into the receiving space and can clamp an electric conductor introduced therein. However, it is also possible, upon an actuation of the screw, for the screw to pull the clamping body upwardly and to press the conductor against a current bar, so no direct contact takes place between the conductor and screw.
The clamping body pocket may be produced from a bent strip-like sheet metal element, which is bent or folded in accordance with the contour of the clamping body pocket. A steel material or a material having a brass-containing alloy is generally used for a clamping body pocket of this type. Furthermore, the clamping body pocket may be produced from a solid profile that is correspondingly machined by cutting methods, such as, for example, sawing, drilling, milling, reaming, thread cutting, in order to obtain the shape of the clamping body pocket. Compared to a clamping body pocket produced from a bent strip-like sheet metal element, the clamping body pocket produced from a solid profile has a more uniform outer contour, as no folding or bending points have to be provided. In addition, a clamping body pocket produced from a solid profile can be formed with smaller dimensions than a clamping body pocket produced from a bent strip-like sheet metal element, so the space requirement of the clamping body pocket can be reduced. In addition, clamping body pockets produced from a solid profile can have a longer threaded bore, so a higher torque, and therefore a higher axial force, can be applied by means of the screw introduced in the threaded bore on the electric conductor clamped by means of the screw. A clamping body pocket formed from a solid profile generally consists of a brass-containing alloy, which has an improved strength and a higher corrosion resistance relative to a clamping body pocket made of steel. In order to improve the machining, in particular in relation to the cutting machining, of the brass-containing alloy, it is conventional to provide the material of the clamping body, and therefore the brass-containing alloy, with lead or to use lead-containing brass alloys. These additions of lead are, however, disadvantageous when it is a question of satisfying the EU guidelines for lead-free products (regulations prohibiting certain materials in the electrical industry or the regulations relating to scrap vehicles). In addition, the production of clamping bodies with a brass-containing alloy is relatively expensive.
The invention is based on the object of providing a solution, in which a clamping body substantially has the properties of a clamping body produced from a brass-containing alloy and simultaneously complies with the EU guidelines and the regulations prohibiting certain materials.